1. Field of Inventions
The present inventions relate generally to implantable infusion devices.
2. Description of the Related Art
Implantable infusion devices have been used to provide patients with a medication or other substance (collectively “infusible substance”) and frequently include a reservoir and a fluid transfer device. The reservoir is used to store the infusible substance and, in some instances, implantable infusion devices are provided with a refill port that allows the reservoir to be transcutaneously filled (and/or re-filled) with a hypodermic needle. The reservoir is coupled to the fluid transfer device, which is in turn connected to an outlet port. A catheter, which has an outlet at the target body region, may be connected to the outlet port. As such, infusible substance from the reservoir may be transferred from the reservoir to the target body region by way of the fluid transfer device and catheter.
One issue associated with implantable infusion devices involves situations where the patient informs the clinician that the therapy provided by the implantable infusion device is not, or is no longer, effective. For example, a patient in which pain medication is being delivered to a particular location within the intrathecal space may complain of back pain if the therapy provided by the implantable infusion device is no longer effective. In order to properly adjust the therapy, the clinician must be able to determine whether the source of the problem is infusible substance related (e.g. the patient has built up a resistance to the medication) or implantable infusion device related (e.g. there is catheter blockage, leak or disconnect, or the fluid transfer device has failed, or the reservoir is empty). Given the fact that the pump and catheter are implanted within the patient, the “infusible substance or infusion device” determination can be difficult, time consuming and invasive.
Accordingly, the present inventors have determined it would be desirable to provide the clinician with an efficient way to determine whether the infusible substance or the implantable medical device is the source of the therapeutic shortcoming.